Valsartan (Formula I) is a specific angiotensin (AT) II receptor antagonist that selectively acts on the AT1 receptor subtype without any agonist activity.

Valsartan is a drug that has very low bulk density and is insoluble in water. The melting point of the free acid form of valsartan is 80-95° C. in the closed crucible, 105-110° C. in the open crucible, and the enthalpy of fusion is 12 kJ/mol. The melting point and the measured melting enthalpy of 12 kJ/mol demonstrated the poor stability of the valsartan particles in the free acid form.
A more stable form of valsartan is required during the process of drying or milling, as well as during the preparation of the formulation. Valsartan is a free acid having two acidic hydrogen atoms, one attaching to a carboxyl group and the other attaching to a tetrazole ring. Therefore, an acidic hydrogen atom or two acidic hydrogen atoms can be replaced with a monovalent or divalent cation. Valsartan sodium salt can improve the solubility of valsartan in solution, but it is hygroscopic and needs to be stored in a cool and dry environment. The valsartan disodium salt disclosed in CN01813039.9 is known to have a melting point starting from 260 and becoming brown at 295. The sodium salt is analyzed by elemental analysis, and the obtained substance (hygroscopic) can be equilibrated in air (C24H27N5O3Na2, 5.36 mol H2O, molar mass 576.05), from which it is known that the sodium salt has a hygroscopicity of up to 20%. It needs to further study the solid form of valsartan sodium salt in order to obtain the valsartan sodium salt with improved physical properties such as solubility and hygroscopicity.
It is difficult to form a salt of valsartan having the desired advantageous properties, however, the crystalline forms of the valsartan disodium salt in the present invention exhibit the desired improved properties.